Recently, according to the wide supply of electronic terminal devices, such as a computer, a smart phone, or a tablet PC, various kinds of electronic document-related programs, with which a user may read, write, and edit an electronic document by using the electronic terminal device, have been released.
The electronic document-related programs include a word processor supporting basic writing and editing of a document, a spread sheet assisting data input, calculation, and a data management, and presentation programs assisting a presentation of a speaker.
In the related art, in order for a user to read, write, and edit an electronic document by utilizing an electronic terminal device, the user needs to directly install the electronic document-related programs in the electronic terminal device, drive the electronic document-related programs, and read or write and edit the electronic document.
However, recently, a high speed Internet environment is established and a wireless Internet environment, in which a user is capable of accessing the Internet anytime and anywhere, is established, and an electronic document-related service is provided to an electronic terminal device that is a client terminal through a server in a remote place, so that a web-based electronic document service, which enables a user to read, write, and edit an electronic document anytime and anywhere even though the user does not install a predetermined electronic document-related program in an electronic terminal device, appears.
The web-based electronic document service supports various client terminals to access an electronic document service providing server, and then to read, write, and edit an electronic document through a browser installed in the client terminals, and supports various client terminals to act simultaneous cooperation in real time for the electronic document, so that the web-based electronic document service is mainly utilized in a company, a group, and the like.
The web-based electronic document service supports a user to read, write, and edit an electronic document through a browser installed in a client terminal if the client terminal can access the Internet, without a necessity for installing a predetermined electronic document writing program in the client terminal, so that it is possible to secure mobility of a user, thereby gradually increasing individual users.
Commonly, in order to support a client terminal connected through a network to perform editing of an electronic document through a browser, the web-based electronic document service is operated in a method, in which when an original electronic document is converted into a markup language-based document and the converted document is provided to the client terminal, the client terminal performs editing of the markup language-based document through the browser.
In relation to this, the web-based electronic document service requires a technology for supporting a plurality of users to simultaneously access one electronic document and simultaneously edit the electronic document, and particularly, research on a technology, in which in a situation where any one user is editing an electronic document, when another user participates in cooperation for simultaneously editing the corresponding electronic document, the documents of both users are synchronized, is required.